1. Darwin’s Other Mistake Michael R. Rose and Theodore Garland, Jr.

2. Darwin’s 1st Mistake Mechanism of heredity wrong
Thought “ an arbitrary number of ductile transmissible gemmules” moved from organs to gonads
Gemmules allowed blending along with inheriting acquired characters
Genetics wasn’t’ properly incorporated into evolutionary biology until the work of Fisher, Haldane, Wright, and Dobzhansky.
Gregor Mendel’s “hard” model for inheritance, which we now call genetics is the correct mechanism for inheritance in eukaryotes.

3. Darwin’s 2nd Mistake
Evolution is gradual and occurs so slowly that it cannot be observed
1896 Illinois Corn Experiment selected for oil content showed observable evolution
Many more studies followed that showed natural selection can be observed
But most people still believe natural selection happens very slowly and is difficult to observe
“natural selection will always act very slowly, often only at long intervals of time, and generally on only very few of the inhabitants of the same region at the same time. I further believe, that this very slow, intermittent action of natural selection accords perfectly well with what geology tells us of the rate and manner at whichs the inhabitants of this world have changed.” – Darwin, Origin of Species.
Believed in gradualism because he was in many respects a disciple of charles Lyell. Lyell essentially founded modern scientific geology.
The cardinal axiom in Lyell’s geology was the idea that change in nature proceeds by gradual, observable, concrete mechanisms, such as erosion, susidence, deposition and the like. Darwin imported this style of thinking into biology.
Other studies: The Illinois Corn Experiment began bidirectional
selection on oil content in 1896 (Hill and Caballero 1992). W. F. R. Weldon
(1901) published a pioneering study of selection in the wild on the morphology of estuarine
crabs. Botanists, such as H. de Vries, began various selection experiments (Falconer
1992). In 1915, W. E. Castle published reasonably quantitative data on the response to
“mass selection” on coat coloration in rats. In the 1930s, animal breeders such as Jay L.
Lush took up the quantitative genetics theory developed initially by R. A. Fisher to implement
well-designed breeding programs. Theodosius Dobzhansky started the “Genetics of
Natural Populations” series of articles in the 1930s, studying selection on the chromosomal
inversions of Drosophila in both wild and laboratory populations, often enlisting the
aid of Sewall Wright. Ecological geneticists such as E. B. Ford and H. B. D. Kettlewell
studied industrial melanism, one of our best examples of natural selection in the wild
(Clarke 2003). Starting from this wide range of groundbreaking work, evolutionary biology
has developed into a substantial body of empirically founded knowledge.
Charles Lyell

4. Experimental Evolution
Definition: “Research in which populations are studied across multiple generations under defined and reproducible conditions, whether in the laboratory or in nature.”
The key to keep biology as a fully scientific field.
More closely resembles physics that most research in biology.
Emphasizes hypothesis testing, trajectories, replication and reproducibility.
Definition is general on purpose to include many types of experiments that involve evolution. Can include experiments on behavior, life history, physiology, morphology of different organisms (bacteria, drosophila, rodents, etc.)
“It is our conviction that the Darwinian inhibition about experimental research on evolution should now be resolutely discared.”
It is only when evolutionary histories are known, controlled and replicated that we can fairly claim to be performing rigorous experimental work.

5. Macroevolution vs Microevolution
Micro – evolution within populations
Macro – change at or above the level of the species
Speciation is on the fuzzy boundary of both.
Macro is difficult to observe because of the time involved but scientists use microevolutionary analyses to address hypotheses about macro.
One consequence of not observing macroevolution is that creationists accept micro as fact but reject macroevolution.
Micro is accepted because of the modern sweet corn and milk from modern dairy.
Macro is also difficult to prove because we don’t know for sure the exact lineage of organisms, if the phenomenon that affects evolution are the same today as millions of years ago, and the random chance events that must have happened, such as the fixation of novel chromosomal translocations or the capture of a prokaryotic cell by another type of cell that led to eukaryotic mitochondria.

6. THE IMPORTANCE OF EXPERIMENTAL STUDIES IN EVOLUTIONARY BIOLOGY Douglas J. Futuyma and Albert F. Bennett

7. The major approaches to analyzing evolutionary processes:
Experimental Evolution
Studies of Natural Populations
Comparative methods
Experimental Evolution- For many generations, a series of replicated populations is exposed to a novel environment, while a parallel series of populations is maintained within the ancestral environment, thereby serving as experimental controls. Usually only a single environmental variable is altered to keep the experiment as simple as possible.
Natural Populations – studying individual species by documenting patterns of variation, such as allele or genotype frequencies, or statistical data on phenotypic characters, within and among populations of a species.
Comparative Methods – comparing similarities and differences among taxa in order to understand the historical evolution of characters in the natural world. Similarity among taxa has long been taken as evidence of common evolutionary history, and divergence of characters in otherwise similar groups, as evidence of adaptation.
Natural Populations -

8. Experimental Evolution
Advantages- Replication and control.
Disadvantages –suited to laboratory rather than to natural situations.
Advantages – By replicating the number of populations exposed to the novel environment, an investigator can, in effect, repeat the opportunity of evolutionary change and determine if the outcome has consistency. Experimental evolution can define and control the degree on environmental change, limiting it to a single factor or any desired combination of factors. Experimental evolution can isolate and analyze the adaptive response to specific environmental factors.
Disadvantages - Because of the requirements for large population size and rapid reproduction, they have to be restricted to certain kinds of organisms that can be easily maintained and bred in quantity in the laboratory.

9. Natural Populations Advantage- offer ecological realism
Disadvantage - lack of ability to replicate results and control variables.
Advantage- the study of geographic variation within species, and its correlation with environmental variables, has been one of the most widely used and successful approaches to demonstrating adaption.
Disadvantage – So many environmental aspects change simultaneously in the natural world that it is difficult to know to which aspect of the environment the population is adapting. In studying natural populations, investigators must be concerned that correlated variables might be responsible for genetic changes, rather than the variable they have identified.

10. Comparative Methods
Advantage- widely used method to understand evolution of characters in the natural world.
Disadvantage-
Correlational
Assumption of parsimony
Disadvantage- Because the Comparative method is correlational, it cannot be directly demonstrated causaly. We do not know if evolution is in fact parsimonious.
Parsimony is a method for choosing the simplest explanation among a variety of possible explanations for phenomena when decisive evidence is unavailable. In evolutionary terms this means grouping organisms or their traits in hierarchies that minimize the occurrence of special events. For example, all mammals are descendants of a fur-bearing, milk-producing ancestor, even though some mammals (e.g., platypus, echidna) produce eggs instead of live young. The most parsimonious explanation is that live bearing is a secondary adaptation that occurred after mammals separated from the other groups of animals.

11. Trade-offs- adaptive gain and correlated loss. Escherichia Coli
2 Examples of the Contribution of Experimental Studies to understand Evolution
Trade-offs- adaptive gain and correlated loss.
Escherichia Coli
Genetic Drift – a founder event (or bottleneck in population size) may initiate new paths of adaptive evolution.
Drosophila pseudoobscura
Trade-offs – “Compensation.” In order to spend on one side, nature is forced to economise on the other side.
Genetic drift - Evolution proceeds slowly in large, stable populations. The prevalent alleles will be those that confer the high fitness on the different genetic backgrounds that they encounter in a large, genetically variable population. However, in isolated population founded by a few colonists will be much less genetically variable ( the “founder effect,” an instance of genetic drift), so selection may instead favor alleles that are good “soloists.”